1. Field of the Invention
The present invention relates to a planar pulse motor, an exposure apparatus including the planar pulse motor, and a device manufacturing method using the exposure apparatus.
2. Description of the Related Art
A planar pulse motor has the feature that it requires no guide for regulating the position of a movable element in the translation direction. For this reason, a planar pulse motor is advantageous to simplifying, for example, a substrate positioning mechanism in an exposure apparatus which transfers the pattern of an original onto a substrate.
Japanese Patent Laid-Open No. 6-121520 discloses a surface pulse motor including a movable element made of a flat magnetic material having projecting teeth on its surface, and a stator made of five-phase electromagnets. In the surface pulse motor described in Japanese Patent Laid-Open No. 6-121520, the movable element includes no coils and can therefore have a light weight.
In general, the exposure apparatus needs to control the substrate along a total of six axial directions: the X, Y, and Z directions and the rotation directions about the X-, Y-, and Z-axes. In the planar pulse motor, as the movable element rotates upon being applied with a moment while the movable element is translated, it may go out of control. Japanese Patent Laid-Open No. 6-121520 neither discloses nor suggests details of rotation control of the movable element.